Electrode assembly and radical unit for the same

ABSTRACT

According to the present disclosure, there is provided an electrode assembly comprising (a) a structure in which one kind of radical unit is repeatedly disposed, the one kind of radical unit having a same number of electrodes and separators which are alternately disposed and integrally combined, or (b) a structure in which at least two kinds of radical units are disposed in a predetermined order, the at least two kinds of radical units each having a same number of electrodes and separators which are alternately disposed and integrally combined.

FIELD OF THE INVENTION

The present disclosure relates to an electrode assembly and a radicalunit for the same, and more particularly, to an electrode assemblyhaving a novel structure that is distinguished from a stack-type or astack/folding type structure and a radical unit for the same.

DISCUSSION OF RELATED ART

This application claims the priority of Korean Patent Application No.10-2013-0058164 filed on May 23, 2013, No. 10-2013-0143285 filed on Nov.22, 2013, and No. 10-2014-0061789 filed on May 22, 2014 in the KoreanIntellectual Property Office, the disclosures of which are expresslyincorporated herein by reference in their entireties.

Secondary batteries may be classified into various types according tothe structure of an electrode assembly. Typically, secondary batteriesmay be classified into a stack-type, a wrapping-type (a jelly-rolltype), or a stack/folding type according to the structure of anelectrode assembly. The stack-type structure may be obtained byseparately stacking electrode units (a cathode, a separator, and ananode) constituting the electrode assembly, and thus an accuratealignment of the electrode assembly is very difficult. In addition, alarge number of processes are necessary for the manufacture of theelectrode assembly. The stack/folding type structure is generallymanufactured by using two lamination apparatuses and one foldingapparatus, and thus the manufacture of the electrode assembly is verycomplicated. Particularly, in the stack/folding type structure, fullcells or bi-cells are stacked through folding, and thus the alignment ofthe full cells or the bi-cells is difficult.

SUMMARY OF THE INVENTION Technical Problem

An aspect of the present disclosure provides an electrode assembly thatis enabled to perform an accurate alignment and simple process through anovel structure that is distinguished from a stack-type or astack/folding type structure, and also provides a radical unit for thesame.

Technical Solution

According to an aspect of the present disclosure, there is provided astackable radical unit comprising a four-layered structure in which afirst electrode, a first separator, a second electrode and a secondseparator are sequentially disposed and integrally combined, or arepeating structure in which the four-layered structures are repeatedlydisposed and integrally combined. An edge of the first separator is notjoined with an edge of the second separator.

According to another aspect of the present disclosure, there is providedan electrode assembly comprising a cell stack part comprising (a) astructure in which one kind of radical unit is repeatedly disposed, theone kind of radical unit having a same number of electrodes andseparators which are alternately disposed and integrally combined, or(b) a structure in which at least two kinds of radical units aredisposed in a predetermined order, the at least two kinds of radicalunits each having a same number of electrodes and separators which arealternately disposed and integrally combined. Edges of adjacentseparators are not joined with each other. The one kind of radical unitof (a) has a four-layered structure in which a first electrode, a firstseparator, a second electrode and a second separator are sequentiallystacked together or a repeating structure in which the four-layeredstructure is repeatedly stacked. Each of the at least two kinds ofradical units are stacked by ones in the predetermined order to form thefour-layered structure or the repeating structure in which thefour-layered structure is repeatedly stacked.

Advantageous Effects

The present disclosure may provide an electrode assembly that is enabledto perform an accurate alignment and simple process through a novelstructure that is distinguished from a stack-type or a stack/foldingtype structure, and also provide a radical unit for the same.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view illustrating a first structure of a radical unitaccording to the present disclosure;

FIG. 2 is a side view illustrating a second structure of a radical unitaccording to the present disclosure;

FIG. 3 is a side view illustrating a cell stack part formed by stackingthe radical units of FIG. 1;

FIG. 4 is a side view illustrating a third structure of a radical unitaccording to the present disclosure;

FIG. 5 is a side view illustrating a fourth structure of a radical unitaccording to the present disclosure;

FIG. 6 is a side view illustrating a cell stack part formed by stackingthe radical units of FIG. 4 and the radical units of FIG. 5;

FIG. 7 is a process diagram illustrating a manufacturing process of aradical unit according to the present disclosure;

FIG. 8 is a perspective view illustrating a cell stack part formed bystacking radical units having different sizes;

FIG. 9 is a side view illustrating the cell stack part of FIG. 8;

FIG. 10 is a perspective view illustrating a cell stack part formed bystacking radical units having different geometric shapes;

FIG. 11 is a side view illustrating a first structure of a cell stackpart including a radical unit and a first auxiliary unit according tothe present disclosure;

FIG. 12 is a side view illustrating a second structure of a cell stackpart including a radical unit and a first auxiliary unit according tothe present disclosure;

FIG. 13 is a side view illustrating a third structure of a cell stackpart including a radical unit and a second auxiliary unit according tothe present disclosure;

FIG. 14 is a side view illustrating a fourth structure of a cell stackpart including a radical unit and a second auxiliary unit according tothe present disclosure;

FIG. 15 is a side view illustrating a fifth structure of a cell stackpart including a radical unit and a first auxiliary unit according tothe present disclosure;

FIG. 16 is a side view illustrating a sixth structure of a cell stackpart including a radical unit and a first auxiliary unit according tothe present disclosure;

FIG. 17 is a side view illustrating a seventh structure of a cell stackpart including a radical unit and a second auxiliary unit according tothe present disclosure;

FIG. 18 is a side view illustrating an eighth structure of a cell stackpart including a radical unit and a second auxiliary unit according tothe present disclosure;

FIG. 19 is a side view illustrating a ninth structure of a cell stackpart including a radical unit and a first auxiliary unit according tothe present disclosure;

FIG. 20 is a side view illustrating a tenth structure of a cell stackpart including a radical unit, a first auxiliary unit, and a secondauxiliary unit according to the present disclosure; and

FIG. 21 is a side view illustrating an eleventh structure of a cellstack part including a radical unit and a second auxiliary unitaccording to the present disclosure.

DETAILED DESCRIPTION

Exemplary embodiments of the present disclosure will now be described indetail with reference to the accompanying drawings. However, the presentdisclosure is not restricted or limited to the following exemplaryembodiments.

An electrode assembly according to the present disclosure includes acell stack part. The cell stack part has a structure obtained byrepeatedly disposing one kind of radical unit, or by disposing at leasttwo kinds of radical units in a predetermined order (e.g., alternately).Thus, the radical unit (s) will be explained first below.

[Structure of Radical Unit]

In an electrode assembly according to the present disclosure, a radicalunit is formed by alternately disposing electrodes and separators. Here,the same number of electrodes and separators are disposed. For example,as illustrated in FIG. 1 a radical unit 110 a may be formed by stackingtwo electrodes 111 and 113 and two separators 112 and 114. Here, acathode and an anode may naturally face each other through theseparator. When the radical unit is formed as described above, anelectrode 111 is positioned at one side end of the radical unit (see theelectrode 111 in FIGS. 1 and 2) and a separator 114 is positioned at theother side end of the radical unit (see the separator 114 in FIGS. 1 and2).

The electrode assembly according to the present disclosure is basicallycharacterized in that the cell stack part or electrode assembly isformed by only stacking the radical units. That is, the presentdisclosure has a basic characteristic in that the cell stack part isformed by repeatedly stacking one kind of radical unit or by stacking atleast two kinds of radical units in a predetermined order. To realizethe above-described characteristic, the radical unit may have thefollowing structure.

First, the radical unit may be formed by stacking a first electrode, afirst separator, a second electrode, and a second separator in sequence.In more detail, a first electrode 111, a first separator 112, a secondelectrode 113, and a second separator 114 may be stacked in sequencefrom an upper side to a lower side, as illustrated in FIG. 1, or fromthe lower side to the upper side, as illustrated in FIG. 2, to formradical units 110 a and 110 b. The radical unit having theabove-described structure may be referred to as a first radical unit.Here, the first electrode 111 and the second electrode 113 may beopposite types of electrodes. For example, when the first electrode 111is a cathode, the second electrode 113 may be an anode.

As described above, when the radical unit is formed by stacking thefirst electrode 111, the first separator 112, the second electrode 113,and the second separator 114 in sequence, a cell stack part 100 a may beformed by only repeatedly stacking the one kind of radical unit 110 a,as illustrated in FIG. 3. Here, the radical unit may have aneight-layered structure or twelve-layered structure in addition to afour-layered structure. That is, the radical unit may have a repeatingstructure in which the four-layered structure is repeatedly disposed.For example, the radical unit may be formed by stacking the firstelectrode 111, the first separator 112, the second electrode 113, thesecond separator 114, the first electrode 111, the first separator 112,the second electrode 113, and the second separator 114 in sequence.

Alternatively, the radical unit may be formed by stacking the firstelectrode 111, the first separator 112, the second electrode 113, thesecond separator 114, the first electrode 111, and the first separator112 in sequence, or by stacking the second electrode 113, the secondseparator 114, the first electrode 111, the first separator 112, thesecond electrode 113, and the second separator 114 in sequence. Theradical unit having the former structure may be referred to as a secondradical unit and the radical unit having the latter structure may bereferred to as a third radical unit.

In more detail, the second radical unit 100 c may be formed by stackingthe first electrode 111, the first separator 112, the second electrode113, the second separator 114, the first electrode 111, and the firstseparator 112 in sequence from the upper side to the lower side, asillustrated in FIG. 4. Also, the third radical structure 110 d may beformed by stacking the second electrode 113, the second separator 114,the first electrode 111, the first separator 112, the second electrode113, and the second separator 114 in sequence from the upper side to thelower side, as illustrated in FIG. 5. As noted above, the stacking maybe conducted in sequence from the lower side to the upper side.

When one of the second radical units 110 c and one of the third radicalunits 110 d are stacked, a repeating structure in which the four-layeredstructure is repeatedly stacked may be formed. Thus, when the secondradical unit 110 c and the third radical unit 110 d are alternatelystacked one by one, the cell stack part 100 b may be formed by stackingonly the second and third radical units, as illustrated in FIG. 6.

As described above, the one kind of radical unit in the presentdisclosure has a four-layered structure in which a first electrode, afirst separator, a second electrode and a second separator aresequentially stacked, or has a repeating structure in which thefour-layered structure is repeatedly stacked. Also, at least two kindsof radical units in the present disclosure are stacked by ones in apredetermined order to form the four-layered structure or the repeatingstructure in which the four-layered structure is repeatedly disposed.For example, the first radical unit forms a four-layered structure byitself, and the second radical unit and the third radical unit form atwelve-layered structure by stacking one of each, that is, two radicalunits in total.

Thus, the cell stack part or electrode assembly may be formed only bystacking, that is, by repeatedly stacking one kind of radical unit or bystacking at least two kinds of radical units in a predetermined order.

The cell stack part of the present disclosure may be formed by stackingthe radical units one by one. That is, the cell stack part may bemanufactured by forming the radical units and then stacking the radicalunits repeatedly or in a predetermined order. As described above, thecell stack part of the present disclosure may be formed by only stackingthe radical units. Therefore, the radical units of the presentdisclosure may be very accurately aligned. When the radical unit isaccurately aligned, the electrode and the separator may also beaccurately aligned in the cell stack part. In addition, the cell stackpart or electrode assembly may be improved in productivity. This is donebecause the manufacturing process is very simple.

[Manufacture of Radical Unit]

A manufacturing process of the first radical unit will be exemplarilydescribed with reference to FIG. 7. First, a first electrode material121, a first separator material 122, a second electrode material 123 anda second separator material 124 are prepared. Here, the first separatormaterial 122 and the second separator material 124 may be the same. Thefirst electrode material 121 is cut into a certain size through a cutterC1, and the second electrode material 123 is cut into a certain sizethrough a cutter C2. Then, the first electrode material 121 is stackedon the first separator material 122, and the second electrode material123 is stacked on the second separator material 124.

Then, it is preferable that the electrode materials and the separatormaterials are attached to each other through laminators L1 and L2.Through the attachment, a radical unit in which the electrodes and theseparators are integrally combined may be formed. The combining methodmay be diverse. The laminators L1 and L2 may apply pressure to thematerials or apply pressure and heat to the materials to attach thematerials to each other. Because of the attachment, the stacking of theradical units may be more easily performed while manufacturing the cellstack part. Also, the alignment of the radical units may be also easilyaccomplished because of the attachment. After the attachment, the firstseparator material 122 and the second separator material 124 are cutinto a certain size through a cutter C3 to manufacture the radical unit110 a. During this process, the edges of the separators are not joinedwith each other.

As described above, the electrode may be attached to the adjacentseparator in the radical unit. Alternatively, the separator may beattached to the adjacent electrode. Here, it is preferable that anentire surface of the electrode facing the adjacent separator isattached to the adjacent separator. In this case, the electrode may bestably fixed to the separator. Typically, the electrode has a size lessthan that of the separator.

For this, an adhesive may be applied to the separator. However, when theadhesive is used, it is necessary to apply the adhesive over an adhesionsurface of the separator in a mesh or dot shape. This is because if theadhesive is closely applied to the entire adhesion surface, reactiveions such as lithium ions may not pass through the separator. Thus, whenthe adhesive is used, it is difficult to allow the overall surface ofthe electrode to closely attach to the adjacent separator.

Alternatively, use of the separator including the coating layer havingadhesive strength makes it possible to generally attach the electrode tothe separator. This will be described below in more detail. Theseparator may include a porous separator base material such as apolyolefin-based separator base material and a porous coating layer thatis generally applied to one side or both sides of the separator basematerial. Here, the coating layer may be formed of a mixture ofinorganic particles and a binder polymer that binds and fixes theinorganic particles to each other.

Here, the inorganic particles may improve thermal stability of theseparator. That is, the inorganic particles may prevent the separatorfrom being contracted at a high temperature. In addition, the binderpolymer may fix the inorganic particles to improve mechanical stabilityof the separator. Also, the binder polymer may attach the electrode tothe separator. Since the binder polymer is generally distributed in thecoating layer, the electrode may closely adhere to the entire adhesionsurface of the separator, unlike the foregoing adhesive. Thus, when theseparator is used as described above, the electrode may be more stablyfixed to the separator. To enhance the adhesion, the above-describedlaminators may be used.

The inorganic particles may have a densely packed structure to forminterstitial volumes between the inorganic particles over the overallcoating layer. Here, a pore structure may be formed in the coating layerby the interstitial volumes that are defined by the inorganic particles.Due to the pore structure, even though the coating layer is formed onthe separator, the lithium ions may smoothly pass through the separator.For reference, the interstitial volume defined by the inorganicparticles may be blocked by the binder polymer according to a positionthereof.

Here, the densely packed structure may be explained as a structure inwhich gravels are contained in a glass bottle. Thus, when the inorganicparticles form the densely packed structure, the interstitial volumesbetween the inorganic particles are not locally formed in the coatinglayer, but generally formed in the coating layer. As a result, when eachof the inorganic particles increases in size, the pore formed by theinterstitial volume also increases in size. Due the above-describeddensely packed structure, the lithium ions may smoothly pass through theseparator over the entire surface of the separator.

The radical units may also adhere to each other in the cell stack part.For example, if the adhesive or the above-described coating layer isapplied to a bottom surface of the second separator 114 in FIG. 1, theother radical unit may adhere to the bottom surface of the secondseparator 114.

Here, the adhesive strength between the electrode and the separator inthe radical unit may be greater than that between the radical units inthe cell stack part. It is understood, that the adhesive strengthbetween the radical units may not be provided. In this case, when theelectrode assembly or the cell stack part is disassembled, the electrodeassembly may be separated into the radical units due to a difference inthe adhesive strength. For reference, the adhesive strength may beexpressed as delamination strength. For example, the adhesive strengthbetween the electrode and the separator may be expressed as a forcerequired for separating the electrode from the separator. In thismanner, adjacent radical units may not be combined with each other inthe cell stack part, or may be combined with each other in the cellstack part with a combining strength differing from a combining strengthbetween the electrode and the separator in the radical unit.

For reference, when the separator includes the above-described coatinglayer, it is not preferable to perform ultrasonic welding on theseparator. Typically, the separator has a size greater than that of theelectrode. Thus, there may be an attempt to bond the edge of the firstseparator 112 to the edge of the second separator 114 through theultrasonic welding. Here, it is necessary to directly press an object tobe welded through a horn in the ultrasonic welding. However, when theedge of the separator is directly pressed through the horn, theseparator may adhere to the horn due to the coating layer having theadhesive strength. As a result, the welding apparatus may be brokendown.

[Modification of Radical Unit]

Until now, the radical units having the same size have been explained.However, the radical units may have different sizes. When stacking theradical units having different sizes, cell stack parts having variousshapes may be manufactured. Herein, the size of the radical unit isexplained with reference to the size of the separator, because,typically, the separator is larger than the electrode.

Referring to FIGS. 8 and 9, a plurality of radical units is prepared andmay be classified into at least two groups having different sizes (seereference numerals 1101 a, 1102 a and 1103 a in FIG. 9). By stacking theradical units according to their sizes, a cell stack part 100 c having astructure of a plurality of steps may be formed. FIGS. 8 and 9illustrate an embodiment in which the cell stack part includes threesteps obtained by stacking the radical units 1101 a, 1102 a and 1103 aclassified into three groups, in which the radical units having the samesize are stacked together, is illustrated. For reference, the radicalunits included in one group may form two or more steps.

When the plurality of steps is formed as described above, it ispreferable that the radical unit has a structure of the first radicalunit, that is, the above-described four-layered structure or therepeating structure in which the four-layered structure is repeatedlystacked. (herein, the radical units are considered to be included in onekind of radical unit even though the radical units have the same stackedstructures but have different sizes.)

Preferably, the same number of cathodes and the anodes are stacked inone step. Also, it is preferable that opposite electrodes face eachother through a separator between one step and another step. Forexample, in case of the second and third radical units, two kinds of theradical units are necessary for forming one step.

However, in case of the first radical unit, only one kind of radicalunit is necessary for forming one step as illustrated in FIG. 9. Thus,when the radical unit has the four-layered structure or the repeatingstructure in which the four-layered structure is repeatedly stacked,number of kinds of radical units may decrease even though a plurality ofthe steps is formed.

Also, in case of the second and the third radical units, at least one ofthe two kinds of the radical units are necessary to be stacked to formone step. Thus, the one step may have at least a twelve-layeredstructure. However, in case of the first radical unit, only one kind ofradical unit is necessary to be stacked to form one step. Thus, one stepmay have at least a four-layered structure. As a result, when theradical unit has the four-layered structure or the repeating structurein which the four-layered structure is repeatedly stacked, the thicknessof each step may be easily controlled when forming a plurality of steps.

The radical units may have not only different sizes but also differentgeometric shapes. For example, the radical units may have differentsizes and different edge shapes, and may or may not have a through holeas illustrated in FIG. 10. More particularly, as illustrated in FIG. 10,a plurality of radical units classified into three groups may form threesteps by stacking the radical units having the same geometric shapes.For this, the radical units may be classified into at least two groups(each of the groups has different geometric shape). Similarly, theradical unit may preferably have the four-layered structure or therepeating structure in which the four-layered structures are repeatedlystacked, that is, the structure of the first radical unit. (Herein, theradical units are considered to be included in one kind of radical uniteven though the radical units have the same stacked structure but havedifferent geometric shapes.)

[Auxiliary Unit]

The cell stack part may further include at least one of a firstauxiliary unit and/or a second auxiliary unit. First, the firstauxiliary unit will be described below. In the present disclosure, anelectrode is positioned at one side end of the radical unit, and aseparator is positioned at the other side end of the radical unit. Whenthe radical units are stacked in sequence, the electrode may bepositioned at the uppermost portion or at the lowermost portion of thecell stack part (see reference numeral 116 in FIG. 11, and thiselectrode may be referred to as a terminal electrode 116). The firstauxiliary unit is additionally stacked on the terminal electrode.

In more detail, when the terminal electrode 116 is a cathode, the firstauxiliary unit 130 a may be formed by stacking outward from the terminalelectrode 116, a separator 114, an anode 113, a separator 112, and acathode 111 in sequence, as illustrated in FIG. 11. On the other hand,when the terminal electrode 116 is an anode, the first auxiliary unit130 b may be formed by stacking outward from the terminal electrode 116,the separator 114, and the cathode 113 in sequence, as illustrated inFIG. 12.

In the cell stack parts 100 d and 100 e, a cathode may be positioned atthe outermost portion through the first auxiliary units 130 a and 130 b,as illustrated in FIGS. 11 and 12. In this case, in the cathodepositioned at the outermost portion, that is, the cathode of the firstauxiliary unit, an active material layer is preferably coated on onlyone side facing the radical unit (one side facing downward in FIG. 11)among both sides of the current collector. When the one side of thecurrent collector is coated with the active material layer as describedabove, the active material layer is not positioned at the outermostportion of the cell stack part. Thus, waste of the active material layermay be prevented. For reference, since the cathode emits, for example,lithium ions, when the cathode is positioned at the outermost portion,the capacity of a battery may be improved.

Next, a second auxiliary unit will be described below. The secondauxiliary unit performs the same function as the first auxiliary unit,which will be described below in more detail. In the present disclosure,an electrode is positioned at one side end of the radical unit, and aseparator is positioned at the other side end of the radical unit. Whenthe radical units are stacked in sequence, the separator may bepositioned at the uppermost portion or at the lowermost portion of thecell stack part (see reference numeral 117 in FIG. 13, and thisseparator may be referred to as a terminal separator 117). The secondauxiliary unit is additionally stacked on the terminal separator.

In more detail, when the electrode 113 contacting the terminal separator117 is a cathode in the radical unit, the second auxiliary unit 140 amay be formed by stacking from the terminal separator 117, an anode 111,a separator 112, and a cathode 113 in sequence, as illustrated in FIG.13. On the other hand, when the electrode 113 contacting the terminalseparator 117 is an anode in the radical unit, the second auxiliary unit140 b may be formed as the cathode 111, as illustrated in FIG. 14.

In the cell stack parts 100 f and 100 g, a cathode may be positioned atthe outermost portion of the terminal separator through the secondauxiliary units 140 a and 140 b, as illustrated in FIGS. 13 and 14. Inthis case, in the cathode positioned at the outermost portion, that is,the cathode of the second auxiliary unit, an active material layer ispreferably coated on only one side facing the radical unit (one sidefacing upward in FIG. 13) among both sides of the current collector, assimilar to the cathode of the first auxiliary unit.

The first auxiliary unit and the second auxiliary unit may havedifferent structures from those described above. First, the firstauxiliary unit will be described below. When the terminal electrode 116is a cathode as illustrated in FIG. 15, the first auxiliary unit 130 cmay be formed by stacking from the terminal electrode 116, a separator114, and an anode 113 in sequence. On the other hand, when the terminalelectrode 116 is an anode as illustrated in FIG. 16, the first auxiliaryunit 130 d may be formed by stacking from the terminal electrode 116, aseparator 114, a cathode 113, a separator 112, and an anode 111 insequence.

In the cell stack parts 100 h and 100 i, the anode may be positioned atthe outermost portion of the terminal electrode through the firstauxiliary units 130 c and 130 d as illustrated in FIGS. 15 and 16.

Next, the second auxiliary unit will be described below. As illustratedin FIG. 17, when the electrode 113 contacting the terminal separator 117is a cathode in the radical unit, the second auxiliary unit 140 c may beformed as an anode 111. As illustrated in FIG. 18, when the electrode113 contacting the terminal separator 117 is an anode in the radicalunit, the second auxiliary unit 140 d may be formed by stacking from theterminal separator 117, the cathode 111, the separator 112, and theanode 113 in sequence. In the cell stack parts 100 j and 100 k, an anodemay be positioned at the outermost portion of the terminal separatorthrough the second auxiliary units 140 c and 140 d as illustrated inFIGS. 17 and 18.

For reference, an anode may make a reaction with an aluminum layer of abattery case (for example, a pouch-type case) due to potentialdifference. Thus, the anode is preferably insulated from the batterycase by means of a separator. For this, the first and second auxiliaryunits in FIGS. 15 to 18 may further include a separator at the outerportion of the anode. For example, the first auxiliary unit 130 e inFIG. 19 may further include a separator 112 at the outermost portionthereof when compared with the first auxiliary unit 130 c in FIG. 15.For reference, when the auxiliary unit includes the separator, thealignment of the auxiliary units in the radical unit may be easilyperformed.

A cell stack part 100 m may be formed as illustrated in FIG. 20. Aradical unit 110 b may be formed by stacking from the lower portion tothe upper portion, a first electrode 111, a first separator 112, asecond electrode 113, and a second separator 114 in sequence. In thiscase, the first electrode 111 may be a cathode, and the second electrode113 may be an anode.

A first auxiliary unit 130 f may be formed by stacking from the terminalelectrode 116, the separator 114, the anode 113, the separator 112 andthe cathode 111 in sequence. In this case, in the cathode 111 of thefirst auxiliary unit 130 f, only one side of a current collector facingthe radical unit 110 b among both sides of the current collector may becoated with an active material layer.

Also, a second auxiliary unit 140 e may be formed by stacking from theterminal separator 117, the cathode 111 (the first cathode), theseparator 112, the anode 113, the separator 114, and the cathode 118(the second cathode) in sequence. In this case, in the cathode 118 (thesecond cathode) of the second auxiliary unit 140 e positioned at theoutermost portion, only one side of a current collector facing theradical unit 110 b among both sides of the current collector may becoated with an active material layer.

Finally, a cell stack part 100 n may be formed as illustrated in FIG.21. A radical unit 110 e may be formed by stacking from the upperportion to the lower portion, a first electrode 111, a first separator112, a second electrode 113, and a second separator 114 in sequence. Inthis case, the first electrode 111 may be an anode, and the secondelectrode 113 may be a cathode. Also, a second auxiliary unit 140 f maybe formed by stacking from the terminal separator 117, the anode 111,the separator 112, the cathode 113, the separator 114, and the anode 119in sequence.

What is claimed is:
 1. An electrode assembly, comprising: a cell stackpart comprising (a) a structure in which one kind of radical unit isrepeatedly disposed, the one kind of radical unit having a same numberof electrodes and separators which are alternately disposed andintegrally combined, or (b) a structure in which at least two kinds ofradical units are disposed in a predetermined order, the at least twokinds of radical units each having a same number of electrodes andseparators which are alternately disposed and integrally combined,wherein edges of adjacent separators are not joined with each other,wherein the one kind of radical unit of (a) has a four-layered structurein which a first electrode, a first separator, a second electrode and asecond separator are sequentially stacked together or a repeatingstructure in which the four-layered structure is repeatedly stacked; andwherein each of the at least two kinds of radical units of (b) arestacked by ones in the predetermined order to form the four-layeredstructure or the repeating structure in which the four-layered structureis repeatedly stacked.
 2. The electrode assembly of claim 1, whereinadjacent radical units are not combined with each other in the cellstack part, or are combined with each other in the cell stack part witha combining strength differing from a combining strength between theelectrode and the separator in the radical unit.
 3. The electrodeassembly of claim 1, wherein the one kind of radical unit of (a)comprises a first radical unit having the four-layered structure or therepeating structure in which the four-layered structure is repeatedlystacked, and Wherein the cell stack part has a structure in which thefirst radical units are repeatedly disposed.
 4. The electrode assemblyof claim 1, wherein the at least two kinds of radical units of (b)comprise: a second radical unit having the first electrode, the firstseparator, the second electrode, the second separator, the firstelectrode, and the first separator, which are sequentially disposed andintegrally combined; and a third radical unit having the secondelectrode, the second separator, the first electrode, the firstseparator, the second electrode, and the second separator, which aresequentially disposed and integrally combined, wherein the cell stackpart has a structure in which the second radical unit and the thirdradical unit are alternately disposed.
 5. The electrode assembly ofclaim 1, wherein the one kind of radical unit of (a) is provided inplurality and the plurality of the one kind of radical units isclassified into at least two groups having different sizes, and whereinthe cell stack part has a structure in which a plurality of steps isformed by stacking the plurality of the one kind of radical unitsaccording to the size thereof.
 6. The electrode assembly of claim 1,wherein the one kind of radical unit of (a) is provided in plurality andthe plurality of the one kind of radical units is classified into atleast two groups having different geometric shapes, and wherein the cellstack part has a structure in which a plurality of steps is formed bystacking the plurality of the one kind of radical units according to thegeometric shape thereof.
 7. The electrode assembly of claim 1, whereinthe electrode is attached to an adjacent separator in each radical unit.8. The electrode assembly of claim 7, wherein an entire surface of theelectrode facing the adjacent separator is attached to the adjacentseparator.
 9. The electrode assembly of claim 7, wherein the attachmentbetween the electrode and the separator is provided by applying pressureto the electrode and the adjacent separator or by applying pressure andheat to the electrode and the adjacent separator.
 10. The electrodeassembly of claim 7, wherein adhesive strength between the electrode andthe adjacent separator in the radical unit is greater than adhesivestrength between the radical units in the cell stack part.
 11. Theelectrode assembly of claim 7, wherein the separator comprises a porousseparator base material and a porous coating layer that is applied to anentire surface of one side or both sides of the separator base material,wherein the porous coating layer comprises a mixture of inorganicparticles and a binder polymer, wherein the binder polymer binds andfixes the inorganic particles to each other, and wherein the electrodeis attached to the adjacent separator by the coating layer.
 12. Theelectrode assembly of claim 11, wherein the inorganic particles of theporous coating layer have a densely packed structure to forminterstitial volumes between the inorganic particles over the overallcoating layer, and wherein a pore structure is formed in the coatinglayer by the interstitial volumes that are defined by the inorganicparticles.
 13. The electrode assembly of claim 1, wherein the cell stackpart further comprises a first auxiliary unit stacked on a terminalelectrode that is an uppermost or a lowermost electrode, wherein, whenthe terminal electrode is a cathode, the first auxiliary unit is formedby stacking from the terminal electrode, a separator, an anode, aseparator, and a cathode in sequence, and wherein, when the terminalelectrode is an anode, the first auxiliary unit is formed by stackingfrom the terminal electrode, a separator and a cathode in sequence. 14.The electrode assembly of claim 13, wherein the cathode of the firstauxiliary unit comprises: a current collector; and an active materialcoated on only one side facing the radical unit among both sides of thecurrent collector.
 15. The electrode assembly of claim 1, wherein thecell stack part further comprises a second auxiliary unit stacked on aterminal separator that is an uppermost or a lowermost separator,wherein, when the electrode contacting the terminal separator is acathode in the radical unit, the second auxiliary unit is formed bystacking from the terminal separator, an anode, a separator, and acathode in sequence, and wherein, when the electrode contacting theterminal separator is an anode in the radical unit, the second auxiliaryunit is formed as a cathode.
 16. The electrode assembly of claim 15,wherein the cathode of the second auxiliary unit comprises: a currentcollector; and an active material coated on only one side facing theradical unit among both sides of the current collector.
 17. Theelectrode assembly of claim 1, wherein the cell stack part furthercomprises a first auxiliary unit stacked on a terminal electrode that isan uppermost or a lowermost electrode, wherein, when the terminalelectrode is a cathode, the first auxiliary unit is formed by stackingfrom the terminal electrode, a separator and an anode in sequence, andwherein, when the terminal electrode is an anode, the first auxiliaryunit is formed by stacking from the terminal electrode, a separator, acathode, a separator, and an anode in sequence.
 18. The electrodeassembly of claim 17, wherein the first auxiliary unit further comprisesa separator at an outer side of the anode.
 19. The electrode assembly ofclaim 1, wherein the cell stack part further comprises a secondauxiliary unit stacked on a terminal separator that is an uppermost or alowermost separator, wherein, when the electrode contacting the terminalseparator is a cathode in the radical unit, the second auxiliary unit isformed as an anode, and wherein, when the electrode contacting theterminal separator is an anode in the radical unit, the second auxiliaryunit is formed by stacking from the terminal separator, a cathode, aseparator, and an anode in sequence.
 20. The electrode assembly of claim19, wherein the second auxiliary unit further comprises a separator atan outer side of the anode.
 21. The electrode assembly of claim 1,wherein the cell stack part further comprises a second auxiliary unitstacked on a terminal separator that is an uppermost or a lowermostseparator, and wherein, when the electrode contacting the terminalseparator is an anode in the radical unit, the second auxiliary unit isformed by stacking from the terminal separator, a first cathode, aseparator, an anode, a separator, and a second cathode in sequence. 22.The electrode assembly of claim 21, wherein the second cathode of thesecond auxiliary unit comprises: a current collector; and an activematerial coated on only one side facing the radical unit among bothsides of the current collector.
 23. The electrode assembly of claim 1,wherein the cell stack part further comprises a second auxiliary unitstacked on a terminal separator that is an uppermost or a lowermostseparator, and wherein, when the electrode contacting the terminalseparator is a cathode in the radical unit, the second auxiliary unit isformed by stacking from the terminal separator, a first anode, aseparator, a cathode, a separator, and a second anode in sequence.
 24. Astackable radical unit comprising a four-layered structure in which afirst electrode, a first separator, a second electrode and a secondseparator are sequentially disposed and integrally combined, or arepeating structure in which the four-layered structures are repeatedlydisposed and integrally combined, wherein an edge of the first separatoris not joined with an edge of the second separator.
 25. The stackableradical unit of claim 24, wherein an entire surface of electrode facingan adjacent separator is attached to the adjacent separator.
 26. Thestackable radical unit of claim 25, wherein the separator comprises aporous separator base material and a porous coating layer that isapplied to an entire surface of one side or both sides of the separatorbase material, wherein the porous coating layer comprises a mixture ofinorganic particles and a binder polymer, wherein the binder polymerbinds and fixes the inorganic particles to each other, and wherein theelectrode is attached to the adjacent separator by the coating layer.27. The stackable radical unit of claim 26, wherein the inorganicparticles of the porous coating layer have a densely packed structure toform interstitial volumes between the inorganic particles over theoverall coating layer, and wherein a pore structure is formed in thecoating layer by the interstitial volumes that are defined by theinorganic particles.